The controlled and accurate delivery of therapeutic drugs to target locations, such as tumors, or other target areas, within tissues of the internal body has long been a goal in the medical industry. However, physiological variables and barriers often prohibit delivery of a therapeutic agent to the target location in optimal concentrations or in a systematic controlled manner. In other instances, the internal body tissue that encompasses the target location can not be subjected to substantial physical trauma, thereby limiting and/or prohibiting direct delivery of the therapeutic agent to the target location itself.
Drug delivery problems are especially problematic in the brain because of the susceptibility of the brain to permanent damage from physical trauma. Conditions/diseases involving the brain rarely involve other areas of the body. In fact, many brain conditions/diseases are rooted in malfunction of selective areas within the brain itself, such is the case for example in stroke, head injury, brain tumors, and many psychotic disorders. Yet, despite the fact that brain conditions/diseases are either localized to the brain or even to a small part of the brain, treatment of these diseases/conditions is predicated on the systemic administration of therapeutic agents to the entire body, for example, through oral, intravenous, or intra-arterial introduction into the circulatory system.
However, many brain diseases/conditions are treated with therapeutic agents that when systematically delivered to the body in quantities to provide the target location with a concentration of the agent to be curative are toxic to other areas of the body or to healthy parts of the brain. Thus, the systemic administration of therapeutic agents to the entire body to treat a brain disease/condition is not possible or less than optimal due to side effects resulting from the drugs reaching other areas of the body or parts of the brain not affected by the disease.
Drug delivery problems to locations in the brain are further complicated by the presence of the blood-brain-barrier. The blood-brain-barrier is an anatomical and physiological barrier that prevents the entry of many charged substance into the brain, thereby limiting the type of therapeutic agents that are used in the treatment of brain pathologies to non-charged (i.e., non-polarized) agents.
Localized delivery of drugs to the brain has been attempted using wafers impregnated with drugs, or through microcatheters delivering drugs using convection enhanced techniques. However these attempts have been largely unsuccessful due to the limited distribution of the therapeutic agent within the brain. Typically, the therapeutic agent will travel only a few millimeters away from its delivery location and in a non controllable fashion. Thus, there is a need for a system and method that can deliver therapeutic agents to target locations within the brain (and other tissues of the body) in a controlled and accurate manner.